1,2-Benzisothiazolin-3-one (BIT) is an effective biocide that is employed, for example, for killing microorganisms (including, for example, bacteria, fungi, molds, yeasts, etc.) in useful aqueous compositions such as, for example, latices. BIT has low solubility in water when the pH is 7.5 or lower, and so it is common to provide BIT in the form (called an “aqueous BIT dispersion”) of BIT particles dispersed in water. It is often desired to provide BIT in a form (called a “BIT concentrate”) that has higher concentration of BIT than is needed for control of microorganisms in useful aqueous compositions. An appropriate amount of the BIT concentrate could be added to a useful aqueous composition to achieve the concentration of BIT that is needed for control of microorganisms in the useful aqueous composition. To be useful, a BIT dispersion concentrate (i.e., a BIT dispersion that is also a BIT concentrate) should have a useful viscosity, and it should be stable.
U.S. Pat. No. 6,306,413 describes compositions that contain BIT, dispersant, and Xanthan gum. Many dispersants are not approved by government bodies for use in compositions that come into indirect contact with food.
It is desired that a BIT dispersion concentrate contains as many ingredients as possible that are approved for use in compositions that come into indirect contact with food. One way to achieve this goal is to eliminate ingredients that are not approved for indirect contact with food. Therefore it is desired to provide a BIT dispersion concentrate that is stable, that has viscosity within a useful range, and that has little or no dispersant.